The present invention relates to the general field of variable-section nozzles for turbomachines, and more particularly it relates to nozzles made up of a plurality of moving flaps forming a ring.
In a conventional architecture for a turbomachine nozzle of variable section, the nozzle is constituted in particular by a ring of moving flaps that are mounted to extend an annular casing of the turbomachine.
The moving flaps are actuated by a control system so as to modify the profile of the primary stream of the turbomachine (i.e. its exhaust section). Depending on the intended configuration, the control system comprises one or more control actuators associated with a more or less complex linkage, e.g. making use of control levers and swivelling-fork connections.
The present invention relates more precisely to a variable-section nozzle of the type in which the control levers for the moving flaps comprise both controlled levers that are actuated directly by actuators, and follower levers that are not actuated directly by actuators but by the controlled levers by means of the swivel-fork connections that transmit displacement drive to the flaps.
With this type of variable-section nozzle, it has been found that in operation (and in particular when the turbomachine fitted with such a nozzle is operating at full speed), not all of the moving flaps making up the ring lie on the same diameter. As a result, while the nozzle is in operation, large leaks occur between adjacent flaps which are due to offsets in the pivoting of the various moving flaps. Such leaks are particularly harmful to the performance of the turbomachine (thrust, specific consumption, etc.).